Espresso and other coffee and milk drinks are often prepared by mixing a powder in water. Traditionally, a milk froth is provided to the drink by steam frothing.
Mixing devices are known for speedier preparation of such beverages and other foods by mixing a powdered food component with a liquid, such as water. These devices typically feed the powdered component into the water, which is often pumped tangentially into a mixing chamber to create a whirlpool to mix the powder into the water. The mixture is then fed to a whipping mechanism, which is usually a rotating plate. The plate aerates the mixture and produces a froth. The frothed mixture is usually dispensed into a container for drinking.
U.S. Pat. No. 5,927,553, for example, discloses a mixing and dispensing apparatus with a cruciform frothing blade. Other shapes of frothing blades are also known. For instance, companies such as Rhea and Zanussi use whippers with an axially short disk with very steep sloped walls. Other whippers have rotors with independent ramps extending from a substantially flat plate. The known devices generally have their greatest efficiency for preparing a small group of products.
There is a need for a mixing device with an improved frothing effect and efficiency. The present invention satisfies this need.